In the case of shed-forming machines in weaving machine construction, in which a pattern card, which has holes and nonperforated parts as control places thereon, is read, the reading needles move periodically toward the pattern card wherein the one of two read results is transmitted automatically as a control impulse through intermediate needles or levers and included a first power amplifier to the element for the second and possible third and last power amplification, namely a draw hook, switching wedge etc., after which this draw hook or wedge lifts, lowers or leaves motionless and in a pattern the heddle. Between two control periods, it is necessary that the members, for example reading needles and intermediate needles, are withdrawn from the influence or control by the pattern card before the first power amplification so that the pattern card can be indexed for the next control operation. During this period, the control of the draw hooks controlled by the first and further power amplifiers must be maintained unchanged in the known devices. However, this fixed control position must be cancelled at the start of the next control period so that the participating members can be programmed again for the next weft. In this returning or restoring of the control members, partly forces of gravitation and partly those of pretensioned springs act as the driving force. Such control systems have several power amplifiers, controlled locking devices for fixing the controlled picture and utilize a considerable time interval during the transmission of an impulse and have complicated sequences of movement which are supported by the force of the gravitation or a pretensioned spring, operate unreliably at higher rotational speeds, which leads to binding errors.
It has been tried to leave out, in such control units, amplifying stages, to operate interengaging sequences of movement with shorter intervals and to reinforce springs. The rotational speed was thereby able to be increased slightly, but the device, which has become sensitive, continued to cause binding errors.
Therefore the object became to build a control system for a shed-forming machine wherein, in the case of higher rotational speeds or short shed, standstill and improved and errorfree operation is assured as well as an increase in production.
This object is achieved with a reading device mentioned hereinabove, in which the reading needle is supported at least in a portion of the power amplifier and is moved with same together or in partial sequence, wherein during reading of a nonperforated part the needle moves relative to the power amplifier, and wherein a lock member is supported in the power amplifier, which lock member is moved into a position transversely with respect to the direction of movement of the power amplifier by the reading needle depending on the read pattern part in such a manner that it during its movement with the power amplifier simultaneously controls a sinker, a draw hook or a switching member of the shed-forming machine.
The inventive device is characterized in such a manner that the reading needle is movably supported in a conventional manner in the power amplifier in a direction of movement toward the pattern card and that it is in positive engagement with a lock member which is movably supported in two positions in the power amplifier in transverse direction to the direction of movement of the reading needle, whereby it is in its two positions each in the path of movement of a control part of a sinker, a draw hook or a switch lever of the control machine, thus the precontrolled lock member and the power amplifier form one unit and also move periodically back and forth as a unit in one draw or in successive draws in direction of the reading movement of the reading needle, wherein at the end of the forward movement, the reading needle has the deepest position in a hole of the card or, in the case of the existence of a nonperforated part, is sunk the deepest in its mounting, while the draw hook or the switching wedge etc. is controlled completely. Forces which come neither from gravity nor from a tensioned spring act on the entire forward movement. The power amplifier moves thereby the lock member automatically regardless of the presence of a hole or a nonperforated part of the pattern card. Furthermore, the lock member transmits during its operating movement released by the power amplifier the control impulse automatically and simultaneously onto a correcting element or the draw hook of a shed-forming machine or the switching wedge of a shed-forming machine having an eccentric ring drive, wherein the correcting element or the switching wedge is blocked at each end of its two controlled positions by a passively acting brake.
The described control unit has a mass and a low friction reading needle and a lock member which is to be precontrolled, which permits a movement of the reading needle with a high speed toward the pattern card, without any danger of damaging the pattern card at the location of a nonperforated part. The precontrolled lock member can control with the same speed and simultaneously therewith the correcting element or the switching wedge, in order to therewith bring the draw hook into engagement with the draw knife or with the locking knife.
As already mentioned, the correcting element or the switching wedge remains in its one-time assumed control position through a brake device or through its special construction. The power amplifying unit can after its forward movement be immediately moved back without influencing the controlled position. The reading needle is thus lifted off, and the pattern card indexed, while the control acts on the movement of the shed-forming machine. From this one recognizes that such a machine can operate quicker and more precise at a simultaneous protection of the pattern card. Due to the fact that during one single control period first the preceding and immediately thereafter the new weft is read, the correct weft-sequence operation of the dobby is assured.
By leaving out the hook or wedge which is to be controlled by the correcting element, the correcting element can control on weaving machines for example the colors, the winding up of material or the heddles for the edge turners or the weaving in of names etc.